Animal Physiology, Institute of Neurobiology, Auf der Morgenstelle 28, University of Tübingen, 72076, Tübingen, Germany.
Bernstein Center for Computational Neuroscience and Institute of Biology, Humboldt-University of Berlin, 10099, Berlin, Germany.
Nat Commun. 2023 Nov 20;14(1):7537. doi: 10.1038/s41467-023-43271-6.
Dopamine neurons respond to reward-predicting cues but also modulate information processing in the prefrontal cortex essential for cognitive control. Whether dopamine controls reward expectation signals in prefrontal cortex that motivate cognitive control is unknown. We trained two male macaques on a working memory task while varying the reward size earned for successful task completion. We recorded neurons in lateral prefrontal cortex while simultaneously stimulating dopamine D1 receptor (D1R) or D2 receptor (D2R) families using micro-iontophoresis. We show that many neurons predict reward size throughout the trial. D1R stimulation showed mixed effects following reward cues but decreased reward expectancy coding during the memory delay. By contrast, D2R stimulation increased reward expectancy coding in multiple task periods, including cueing and memory periods. Stimulation of either dopamine receptors increased the neurons' selective responses to reward size upon reward delivery. The differential modulation of reward expectancy by dopamine receptors suggests that dopamine regulates reward expectancy necessary for successful cognitive control.
多巴胺神经元对奖励预测线索做出反应，但也调节前额叶皮层中的信息处理，这对认知控制至关重要。多巴胺是否控制前额叶皮层中的奖励预期信号，从而激发认知控制，目前尚不清楚。我们在一项工作记忆任务中对两只雄性猕猴进行训练，同时改变完成任务后获得的奖励大小。我们在对侧前额叶皮层记录神经元的同时，通过微电渗流刺激多巴胺 D1 受体（D1R）或 D2 受体（D2R）家族。我们发现许多神经元在整个试验过程中预测奖励大小。D1R 刺激在奖励线索后表现出混合效应，但在记忆延迟期间减少了奖励预期编码。相比之下，D2R 刺激在多个任务期间增加了奖励预期编码，包括提示和记忆期间。多巴胺受体的刺激都增加了神经元对奖励后奖励大小的选择性反应。多巴胺受体对奖励预期的不同调节表明，多巴胺调节成功认知控制所需的奖励预期。
